Lesson Materials

Per Class

• 2 clear tubs filled with room-temperature water

• 9 empty coffee cups

• 1 coffee cup filled with warm water

• electric coil or kettle

• red food dye

• blue food dye

• 4 pipettes

• paper towels

• meat thermometer

• electric coil or kettle to heat water

• ice or ice water

• 2 oven mitts

• tape

• chart paper

• markers 

Per Group

• 1 clear tub

• 5-6 coffee cups

• 1 cup with 5 mL of red dye

• 1 cup with 5 mL of blue dye

• 2 pipettes

• tap water

• thermometer(s)

• ruler

• paper towels

• handout: Air Movement in Different Conditions

Per Student

• science notebook

Prep

Review 

• Lesson Plan

• Slides

Prepare 

• Make copies of handout: Air Movement in Different Conditions (one copy for each lab group)

Convection in Fluids: Demonstration and Student Investigation

• Group Size: Split the class into 6-8 groups, depending on your class size.

• Setup: Watch the teacher demonstration video Investigation Set Up OSE to see how to deploy the dye into the water with minimal disturbance and how to do the first demonstration.

  • Put one tub and five coffee cups at each lab station. Put one tub on top of four upside-down coffee cups, one at each corner. Reserve one coffee cup for students to fill with hot, cold, or warm water. Each lab station should have one or two meat thermometers. Have a few extra coffee cups for groups that might need two (e.g., the group that tests having a lot of thermal energy input over a larger area will need two cups of hot water).

  • Put 5 mL of red and blue food coloring into separate cups for each lab station. Place two pipettes and a paper towel at each station. 

• Notes for During the Lab: Use an electric coil in a ceramic coffee cup (or use an electric kettle) to heat water for students to fill their cups. The water should not be warmer than 160℉ when poured, to avoid the risk of burns. If you boil the water, measure its temperature as it cools to make sure it is not too hot when students use it. You can also pour less hot water and then add cool water to speed up the cooling. Also, have warm tap water available.

• If your sink doesn’t produce cold water, provide a tub or ice chest with ice water so students can add small amounts to their tub to lower the water temperature.

• There are several options for having students control the temperature gradient in the tub system. You could have these test conditions:

  • with hot water in the cup

  • with lukewarm water in the cup

  • with cold water in the cup

  • with two cups of hot water

  • with one cup of hot water and one of cold water

  • with hot water in cups below and ice on top of the tub

• Safety: For the groups using very hot water, have the students use oven mitts to handle the cups.

• Disposal and Storage: The tubs of water can be emptied into a sink, and the pipettes either disposed or rinsed for reuse. The tubs are designed to be stacked for storage, with all pipettes stored inside. The coffee cups are intended to be reused as well and can be dried and stored, too.